New diagnoses for two types of skin cancer have increased in recent years, according to a Mayo Clinic-led team of researchers. Their paper, published in the Mayo Clinic Proceedings, used medical records from the Rochester Epidemiology Project to compare diagnoses of basal-cell carcinoma and squamous-cell carcinoma––both nonmelanoma skin cancers––between 2000 and 2010 with diagnoses in previous years. The Rochester Epidemiology Project is a medical-records linkage system and research collaborative in Minnesota and Wisconsin.
The researchers reported that, between 2000 and 2010, diagnoses of squamous-cell carcinoma increased 263%, and those of basal-cell carcinomas increased 145%. They compared the 2000–2010 period with 1976–1984 and 1985–1992.
Women 30 to 49 years of age experienced the greatest increase in diagnoses of basal-cell carcinoma, whereas women 40 to 59 years of age and those 70 to 79 years of age experienced the greatest increase in squamous-cell carcinomas.
Men had an increase in squamous-cell carcinomas between the first and second periods studied (1976–1984 and 1985–1992), but experienced a slight decline during the 2000–2010 period. However, for basal-cell carcinomas, men older than 29 years of age showed similar increases in diagnoses during the 2000–2010 period.
“We know that the sun and some artificial sunlight sources give off skin-damaging ultraviolet [light],” said senior author Chrisian Baum, MD, a Mayo Clinic dermatologist. “This skin damage accumulates over time and can often lead to skin cancer.”
“Despite the fact that sunscreens and cautionary information have been widely available for more than 50 years, we saw the emergence of tanning beds in the 1980s, and tanning––indoors or out––was a common activity for many years,” he said.
Although Baum noted that tanning has slowed, tanning beds still exist, and beaches will never be empty. But what people should remember is that skin damage accumulates, he said, and “eventually those blistering sunburns of your youth and hot, reddened skin, and peeling shoulders of your adulthood can add up to one or more skin cancers.”
The authors also reported that shifts in exposure to UV light may be the reason for a location shift in where the cancer tumors are found. During the earlier periods, both basal-cell and squamous-cell carcinomas were diagnosed more often on the head and neck. But, during the most-recent period, the records showed that basal-cell tumors on the torso increased, as did squamous-cell carcinomas on the arms and legs.
Baum said that the risk of cancer should provide the ultimate argument for using sunscreen every day, year-round, on all exposed skin.
“Use sunscreen,” he said. “This includes on your left arm for those who do a lot of driving. UV rays can penetrate car windows and exposed skin––even when the sun isn’t shining. UV rays bounce around under the clouds, off the snow, buildings, and more, causing damage––even on gray days.”
Using the Rochester Epidemiology Project medical-records linkage system, the researchers were able to identify nearly all of the adult residents of Olmsted County, Minnesota, who received an initial diagnosis of the most common nonmelanoma skin cancers—basal- or squamous-cell carcinoma, or both––during the 2000–2010 period and the comparison years.
“There is no tumor registry for these types of cancer,” Baum said. “So it is difficult to have accurate estimates of the national or worldwide impact of these cancers. However, because the Rochester Epidemiology Project contains health care information for virtually all residents of Olmsted County since 1966, it provides a good proxy for information on many global population health concerns.”
Source: Mayo Clinic; May 15, 2017.